Germany reviews its underground activity 14 Dec 2017

Roland Herr for TunnelTalk

The biennial conference organised by STUVA every two years has established itself as a major convening of the tunnelling industry of Germany and further afield. This year the event in Stuttgart in early December attracted 1,920 participants from 33 countries (up from 1,850 and 26 countries for the 2015 event) and hosted a programme of 65 parallel presentations and a 3,250m2 exhibition hall of more than 200 exhibitors. Freelance journalist Roland Herr represented TunnelTalk at the event and compiled our conference report.

Some €270 billion is be invested in 1,000 projects across its transportation networks from now to 2030 was the keynote message from Rainer Bomba, Permanent Secretary of Germany’s Federal Ministry of Transport and Digital Infrastructure, and promising a bright future for the underground excavation industry for the nation. And not only by good luck did he address several times Dr Martin Herrenknecht sitting in the main auditorium, but he could equally address, more or less, all leaders of the tunnelling business in Germany.

Germany, an important ITA Member Nation

Tarcisio Celestino, President of the ITA International Tunnelling and Underground Space Association, underlined the importance of Germany within the international underground construction industry. “The world has an annual USD$1 trillion shortfall in infrastructure spending, so the opportunities are huge.” And there are all over the world good examples, especially in tunnelling, where made-in-Germany is part of the success. “Germany has always been an important Member Nation for ITA with Professor Günter Girnau and Professor Alfred Haack, both former senior members of the STUVA research centre, as former ITA presidents.”

Bomba talked about mobility as is one of the most important preconditions for prosperity, and not only in Germany. For that reason, “investment in high-capacity, modern transport infrastructure is one of the keys for the sustainable maintenance of the competiveness of Germany”, he stated.

In 2017 the German Government invested about €12.8 billion in transport infrastructure and that will increase again to €14.4 billion in 2018, an increase of 40% since 2014. Building information management (BIM) is also an important tool in Germany to ensure that new construction projects as well as maintenance and repair projects are completed on time and within budget. BIM is now reality in Germany and worldwide.

One of the centrepieces of the German unity transport project, the direct link from Munich to Berlin between Ebensfeld and Erfurt, opened in December and on the last day of the STUVA conference. With huge publicity and German Chancellor Angela Merkel in attendance, the first ICE inaugurated the connection. Unfortunately the opening was plagued by train breakdowns, with no single day in the first week without delays, but the tunnels are without any doubt perfect!

A review the Rastatt tunnel collapse (left) provided the facts as they unfolded (right) and as already reported

In his keynote, Ronald Profalla, Management Board Member for Infrastructure of Deutsche Bahn AG, gave an overview of the huge future investments for the rail system in Germany. The network of 33,380km in 2016 runs through 708 tunnels with a total length of more than 500km. Under the next finance agreement with the Federal Government, DB will have invested €28 billion in the period from 2015 to 2019, with about €1 billion for the renewal and maintenance of 18 mostly historic tunnels. Investments are also planned for further new projects to renew the existing network.

STUVA 2017 prize winner: Deutsche Bahn AG

Since the first prize awarded in 1997, the annual STUVA prize is an anticipated announcement. This year, the 2017 Prize was awarded to Deutsche Bahn AG for the overall achievement of the company, through decades, on the numerous new lines and innovations introduced in constructive collaboration with the consultants and construction companies involved. Professor Ziegler, Chairman of the STUVA Board, handed over the award to Dieter Thormann, Mike Flügel and Board Member of DB Netz AG Professor Dirk Rompf (left to right).

After an impressive opening, the mass of delegates flocked to the coffee break in the exhibition hall. It is not easy to decide where to meet more colleagues and business partners in an exhibition: at Herrenknecht, Wayss & Freytag, Züblin, A.S.T. Bochum, Robbins, Bögl, TPH stands – the list must be incomplete because the exhibition was crowded not only in the breaks. Networking on the highest level of quality.

With two technical lecture sessions, it is difficult to decide which one to join, but this variety of topics drives the STUVA conference once more to an event that everybody marks in the diary before the current one is closed. The following are some of the more interesting sessions and topics, but every single lecture was worth joining.

Overview Rastatt drive collapse

Despite a bulging auditorium of absolutely curious tunnellers, there was no explanation of how and why the TBM rail tunnel excavation under the main high-speed rail route between Germany and Switzerland at Rastatt collapsed in August 2017 and instead, when Professor Dirk Rompf, Member of the Management Board of DB Netz AG, and Edgar Schömig, Board Member of Ed Züblin AG, came to the stage at the end of the first session of the first day, they gave an overview of the facts of what happened, describing the situation at the job site and measurements adopted to control and repair the damage. During the presentation it was evident that the consequences could have been much worse and that it was the cooperation between client and contractor on the day that contained the collapse scenario.

It was really a pity not to get more information about the possible reasons for the collapse, but it is on the other hand fair enough that during investigation all kind of speculation is not productive. A public report following the investigation is not expected until Spring 2018 at the earliest.

International projects

International experience with various views on problems and solutions, tunnelling technologies and special conditions were represented with presentation about:

Save the date for 2019

STUVA is “a meeting point for the international tunnelling family”, said Professor Martin Ziegler, Chairman of the Board of STUVA, and to be honest, it is absolutely true that it is one of the best! There is no other conference to compare with the combination of high quality lectures (in German and parallel in English), the a steadily increasing number of exhibiting companies from all over the industry, and the meeting point for decision-makers and suppliers. The two days of the event were fully packed with information, tunnelling and networking. The next STUVA Conference will be in Frankfurt am Main, 26 to 28 November 2019.

The Follo Line as the first tunnel project in Norway with a TBM and precast segmental lining

Construction logistics to allow simultaneous tunnel excavation and station construction for the Cityringen Metro in Copenhagen, Denmark

Implemantation of risk management procedures, a solid contractual basis and reliable cost control systems as used on the Ceneri Base Tunnel between Austria and Italy

The problems and solutions of clogging and wear effects during the construction of the Ismailia road tunnel under the Suez Channel in Egypt

Very special challenges and solutions with the rock mechanics at the new Västlänken rail tunnel in Sweden

Construction of the deep intermediate shafts between the TBM and NATM sections of the Semmering Base Tunnel in Austria.

Metro Tunnelling in Singapore

In his presentation Andreas Raedle, Tunnel Leader at Arup Singapore, gave an overview of the tunnelling activities to expand the Metro system requiring 30 TBMs to excavate the twin tunnels of the 30km long, entirely underground, Thomson Line. Currently 20 TBMs are in operation and 22 underground stations with five interchange stations are under construction. The relevance of STUVA as an international event was signified with German national Raedle delivering his presentation in front of more than 1,000 listeners in English.

Single-layer drained segment construction

There are not so many new developments in the industry, but the STUVA illustrated it important role as a Research Association for Underground Transportation Facilities when Christian Thienert from STUVA presented details of a single-layer drained segment construction with water-permeable grouting of the annular gap. To extend the application of mechanised tunnelling with a single-pass segmental lining in solid rock, the concept is to use an annular gap material with a kf-value > 10-4 m/s, which is capable of being pumped and suitable for drainage. The idea is to achieve an open-pored and water-permeable structure with sufficient strength to ensure the bedding of the segments with a defined foaming of cement suspension with a foam generator.

“We are very proud of the growing reputation of the STUVA Conference,” said Dr.-Ing. Roland Leucker, Executive Director of STUVA, the Research Association for Tunnels and Transportation Facilities, based in Cologne, Germany

Steel fibre reinforced segments

Steel fibre reinforced (SFR) segments are becoming the norm TBM tunnels are being excavated through saline ground water. As well as improved resistance of the elements and durability, SFRC segments offer the advantages of a considerable reduction in steel reinforcement and production costs together with higher impact toughness and more favourable crack distribution. Carola Edvardson, Technical Director of COWI in Denmark, gave an interesting overview of SFRC segment design, durability and case studies of current projects in Denmark, UK and Switzerland.

Tunnel operations

For the second time, STUVA included in the programme and parallel session on tunnel operations, illustrating the existing gap of information in all aspects of tunnelling that are outside the conventional technologies. Here is a chance for the organizers of STUVA to develop the concept of lectures and exhibition stands into a fully rounded and perfect tunnel event.

Within the presentations of the session this year there were some important presentations.

Lessons learned from a tank trailer fire in the Skatestraum subsea road tunnel in Norway were described by Arild Petter Sovik from the Sovik Consulting, in addition to the safety strategies and new regulations for tunnels in Norway as a result of such incidents.

Two new door systems for tunnels were presented by Christian Nutrice from Elkuch Bator in Liechtenstein. After an overview of accidents, hazards, technical solutions and escape behaviour, always with the door systems in mind, he showed a forecast in the development of a prefabricated door system which shortens significant the assembly of the safety doors in cross passages. Another development is a door system that is very easy to open despite a lower or higher pressure in the environment.

Safety in road tunnels, maintenance, energy savings, road tunnel ventilation, rescue concepts, transport tunnels and geothermics, IT security and much more were topics within session presentation.

It was also no surprise that BIM, digitalisation and monitoring has become an important topic for the STUVA programme with some very interesting national and international examples of BIM application presented during the conference.

Famous Keller Bar networking

After a full programme, the first day came to sunset and the traditional social evening with hungry and thirsty tunnellers packed into the Keller Bar. Everyone should have been tired of talking and listening, but not the tunnellers. All were awaiting the networking highlight to chat and drink the last beer, and the last beer, and the last beer until shortly before sunrise.

In anticipation of the next event, buy your 2019 diary right now and block the date and place for the next STUVA Conference in Frankfurt am Main on 26 to 28 November 2019.

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